The present invention concerns the preparation of chlorinated pyridine derivatives.
The chlorinated pyridine derivatives of the present invention are known compounds having been previously prepared by a number of processes. These compounds, namely 2,3,5,6-tetrachloropyridine and pentachloropyridine, have uses such as herbicides, pesticides, etc., and are also employed as chemical intermediates in the preparation of other highly desired herbicide or pesticide products. Previous methods for preparing such compounds include those described in U.S. Pat. No. 3,538,100 and the prior art noted therein wherein pentachloropyridine and 2,3,5,6-tetrachloropyridine have been prepared by chlorination of liquid 2,6-dichloropyridine at temperatures of at least about 180.degree. C. and in the presence of a metallic halide catalyst.